Thank you much nate for informative details and appreciate your help
I hope you’ll come back and update us on what you decide to get and how it’s working out for you.
After thinking about this a bit, I believe you would be well served by a so called dual-fuel or multi-fuel light. These lights have the versatility to allow you to experiment with multiple types of batteries to see what works best for you. Or, perhaps even better, roll with a rechargeable Li-ion battery in the light and bring some non-rechargeable Lithium batteries for backup. Something to be aware of is that performance (outputs & runtimes) does change with different power sources.I would recommend looking at the following (in no particular order):- Flashlights that can run on the user’s choice of 1x18650 or 2xCR123A batteries. Example: Fenix PD35R ACE. Flashlights like this often feature a large number of output modes, allowing the user to dial up the right amount of light for nearly any situation: low, eco, or moonlight modes offer impressive runtimes and an appropriate amount of light for reading or other close work, while high and turbo modes offer excellent brightness and throw if needed (though only for a relatively short period of time). Disadvantages are that lights of this type tend to be large, heavy, and expensive relative to other options.- Flashlights that can run on the user’s choice of 1x14500 or 1xAA battery. Example: Lumintop Tool AA 3.0. Lights of this type tend be smaller, lighter, and less expensive than other options, while still offering adequate brightness and runtime for relatively close up, short- to medium-time use. These lights can usually even run on the very common AA alkaline batteries, though I would avoid long term storage with those due to leakage concerns. The main disadvantages are that output and runtime don’t hold a candle (pardon the flashlight puns) to some of the larger options.- Flashlights that can run on the user’s choice of 1x16340 or 1xCR123A battery. Example: Fenix PD25R. Flashlights of this type are something of a “middle of the road” option between the previous two.
I don't believe there's a single flashlight that will properly operate at -30C, which I regularly experience…
If it is going to be used in the car, I recommend the strongest "head" light you can get. You never know, you may need to look under the hood after some mechanical issue and you need both hands